Resinous liquid composition



Patented 0118,1938

4 UN TED STATES assmous mourn com'rosrrloiv PATENTwOFFlE mu m. Novotny, Philadelphia, Pa, assignor, by

assignments, toDurite Plastics, Incorpo- Insane rated, l'hiladelilh l, Pa, a corporation of Penn- No Drawing. Application July 14, 1936, Serial No. 90,4 89

llClaims. (sizes-5i) cles", Serial No. 90,490, filed July 14, 1936, there is set forth the use and advantages of the resinous liquid composition of the present invention when employed as a coating and bond for the abrasive grains and as a bond ior an added dry pulverised synthetic resin. When so used, there is produced a wet abrasive mix which is selfconverted to a dry granular mix, capable of being cold molded. The resinous liquid compositions when manufactured in accordance with the principles of the present invention possesses such physical and chemical characteristics that U it reacts with the added dry resin to produce a wet mix wherein there is no unsuspended or va-- o must be limited, and this is eiiectcd by carrying gr'ant pulverised resin (the resin being then all coated on the abrasive grains), which wet mix "then sell-converts or spontaneously changes to a a dry granular mix composed of discrete all-resincoated abrasive particles. This resinous liquid composition is alsogenerally useful in the cold molding art as a coating for various fillers and particularly inorganic tillers.

' The resinous liquid composition which ,iunctions as a converting liquid in the process (converting the mix from the wet-to-dry state) as well as an intermediate and final bond in the molded product, consists of three or four types 35 o! naming huh govern the converting action oi'themcfiiiiisition. These materials will be re-' 4ei'red to herein as coherer, incoherer, regulator and solubiliser. In the case of certain water soluble gums or resinous products the solubilizer 40 may be omitted, but in the case of phenol-formaldehyde resinsthe solubiliaer is an essential material.

. The "term "coherer" is used to designate speciilcally certain unreacted phenol, phenol alco- 45 hols, but preferably certain low resiniflcation reaction products. This product called the coherer should be more or less miscible with the inco- Y la'rg eamountoiluwly'reaetedresinousproducts.

This product isjas will be seen, a solvent for the regulator (e. g. the more highly reacted prod- 'ucts) It is likewise a solvent for any addeddry pulverized resin as used in the molding mix, or at least a solvent for a major portion of such pul- I verized resin. The viscosity of this coherer product should be relatively low, yet preierably over one second and not over iive seconds at 25 C. it

timed in an R. P. C. (R. P. Cargille) viscosity tube. The product should be substantially nonl0 volatile and more or less neutral; and it, this coherer were separated iromthe rest of the composition and were by itself mixed with the dry pulverized resin in the ratio of say one part or so 01 the coherer to three parts of the pulverized resv1| in, the mass would flux down to a homogeneous melt and a strong inherent structure would result with the coherer a compatible and homogeneous part of the solidified resin. While the coherer must be a good solvent for the dry resin, yet at the same time the solvent properties out the reaction to determined limits.

As a further explanation of the coherer, I might state that in the case 01' phenol-iormaldehyde resins, phenols, cresols, etc. are too poweriul as solvents, and that by determining the percentage oi such phenol and cresol and regulating the reaction I convert these to substances which are chemically akin thereto, but of greater complexity, that is, higher molecular weight and higher viscosity, such as the simpler condensation polymerization products resulting through the reaction of the phenol and formaldehyde. In general with the reaction between phenol and formaldehyde on substantially an equal molar basis with a suflicient amount oi catalyst to provide an energetic reaction I am enabled to pro-- vide a resinous reaction product containing a sumcient amount or these low resiniflcation reaction products which act as the coherer. Pref-- erably I use a basic catalyst such as sodium hydroxide.

The term "incoherer is used to designate a non-resinous liquid body of low viscosity. high surface tension, volatile at room temperature, chemically substantially neutral and of such a nature that the solubiliser (e. g. NaOH) vwill render this incoherer more or less a solvent for the regulator and the dry or solid pulverized resin. Water is a specific and preferred example 01' this product where a phenol-aldehyde resin system is used, although other volatile liquids having solvent characteristics adapted to the specific resinous system employed are useful.

The incoherer should be compatible and retained in substantial quantities without separation in combination with the other ingredients. As a specific illustration the presence of water is essential for the attaining of the self-conversion of the wet to dry" feature in a phenol-aldehyde 'resin system. The function of the water is at least three-fold. Firstly, it aids in lowering the initial viscosity without increasing the solvent properties for the dry or solid resin, as would be the case if the water were replaced by other thin fluid materials having a greater solvent ac-' tion such as phenol, phenol alcohol and the lower condensation products; secondly, the water increases the eflective surface tension of the fllm surrounding the coated filler such as the abrasive grains; and, thirdly, it plays an important part in self-converting a wet mix to a dry state.

The term regulator is used to designate a material which is chemically akin to both the solid pulverized resin andthe coherer, but which in molecular complexity is. closer to the solid pulverized resin than the coherer- As in the. case of the coherer, the regulator likewise comprises a graded mixture of more highly reacted products and this grading seems to be most desirable. The characteristics of the regulator and coherer with respect to the solid resin require that a chemical compatibility or kinship is desirable and that while the coherer represents lowly reacted products, the regulator represents products of relatively high molecular weight. The solid pulverized resin to be used therewith also comprises products of higher molecular complexity. Between these, however, there is no deinite cleavage line and the reaction products overlap.

The term solubilizer is used to designate a material which is used only in instances where the-best available incoherer (water) -is insufriciently compatible with the solutions that resultwhen resin is dissolved by the resinous liquid. This is the case where phenol-formaldehyde resins are used in the making of the resinous liquid. The solubilizer consists of a strongly alkaline body such as sodium hydroxide or its equivalents; and its purpose is to prevent the incoherer from extending an excessive insolubilizing eifect upon the coherer. The incoherer including the alkali comprises an aqueous alkaline liquid and converts the resin of the resinous liquid to an aqueous alkaline solution in that it is more or less of a solvent for the regulator and the solid pulverized resin subsequently used. This stabilizer, such as NaOH, is useful for a variety of reasons. Firstly; it aids in regulating the water tolerance and the rate at which water concehtrates on the outer surfaces as the abrasive grains become coated with the resinous mixture. The NaOH also aids in controlling the rate of mutual solution. and in lowering the surface'tension. In a sense the NaOl-l may be looked upon also as a coupling-agent between the water and the non-water portions that result from the solution of the solid resin into the solvent portions of the resinous liquid. V

The initial surface tension of the resinous liquid should be sufficiently low so as topermita ready and complete wetting of the abrasive grains or other filler thereby and by the initial solution products that result when solid resin dissolves into it. -The initial viscosity-of the resinous liquid should be low'enough'to permit of a ready flow so that the forces of suriace tension can exert their full play and so that all irregularities in the grain or other filler may be filled without air entrapment.

The resinous liquid is possessed of certain definite characteristics which are given generally in the following tabulation, but which are given as average limits in greater detail in the tabulation entitled Resinous liquid data, comprising various test constants and limits.

1. Viscosity must be kept relatively low.

2. Viscosity must increase rapidly when solid pulverized resin is dissolved therein.

' 3. Solvent power for the solid pulverized resin, both with respect to the rapidity with which it can dissolve the solid pulverized resin and the quantity thereof before the liquid passes into a phase describable as a soft solid. 1

4. The final and most important criterion is the ability to yield self-converting wet to dry abrasive mixes within a reasonably of time.

Where a phenol-formaldehyde resin is used in preparing the resinous liquid the following "approximate optimum percentage composition comprises the four divisions of such fluid.

short period Apmoxi. High Low mate optimum Percent Percent Percent i. 70 I) 40 2. is 28 8. 40 10 M 4. l0 0. 2

It will be noted that in this tabulation under approximate optimum" data, I show the approximate optimum admixtures and it is only this column which therefore totals 100%, The percentages given under high and low should be considered as high and low limits for each one ofthe four functional products with the understanding that considering each one of these on the basis of high or low limits that adjustments must be made in the others to provide a resinous liquid which produces a composition mix selfconverting from the wet to the dry state.

While the resinous liquid data gives average conditions covering the resinous liquid as a total, for simplicity it should be understood that the regulator and the coherer are each possessed of specific physical characteristics and each can be easily differentiated from the other in that the regulator possesses OH groups inactivated in the range of from 30 to 50% and the coherer represents low reaction products whose per cent inactivated phenolic (OH) groups lies approxirange of 20 to 30%. In a properly formulated resinous liquid, the regulator and coherer exert,

a mutual influence upon one another and these materials in general will yield a figure including the borderline material giving certain per cent inactivated phenolic (OH) for the resinous liquid; and it is this figure which is given in the resinous liquid data as an average.

Given a liquid mixture it is possible by 11- ous. means to determine the relative quantities of regulator and coherer. The regulator repaldehyde is .-mmm all combined, and givresents highly'polymerised and condensed material whereas the coherer consists of low resinification reaction products. This permits one to differentiate between these types by determining the water tolerance in methanol of the resinous liquid. ".llhe highly polymerized and technique one can derive figures that are proportional to the ratio of highly water insoluble to very water soluble materials and thus the ratio of highly ,resinifled to lowly resinified materials which in turn is correlated to the ratio of regulator to coherer.

It will be apparent from the foregoing that the resinous liquid product can be' prepared from various resins and for that matter from previously prepared solid resins by simply mixing together sodium hydroxide, water, lowly reacted phenol-formaldehyde products and more highly reacted phenol-formaldehyde products, and that other solid resinoid materials such as shellac, gum accroides, vinyl and styrol resins, ethyl cellulose, other resinoid bodies such as cellulose esters or others may be used. However, where the phenol resin is used, the most suitable product is obtained by reacting the material complete from the beginning in order to provide an aqueous alkaline resin solution having the characteristics called for in my resinous liquid data.

Example I.-In making my resinous liquid composition I preferably use phenol and commercial U. S. P. formaldehyde in proportions which will be approximately stoichiometrlc when the reaction is completed, or by weight the ratio is 1:0.9, and place such product into an enclosed still provided with a high speed agitator and a condenser of large surface capacity which is arranged for refluxing and distillation. In charging this kettle I preferably start of! with the entire quantity of phenol and I add thereto a'solution of of water and I then add approximately of the total. formaldehyde called for, which is approximately the quantity of higher reacted resinous products which are to constitute the approximate optimum of regulator called for in the specification. With the condenser set for refluxing, the temperature is gradually brought up to the boiling point'and a tie up is produced which will provide a substantial quantity of these more highly reacted products comprising the regulator. At this point appropriate tests are made and a. determination of the gram moles OH groups inactivated as contained in the kettle'are definitelydetermined. As substantially We now proceed with the balance of the reaction adding additional formaldehyde and this is preferably added at a kettle contents temperature of 150 F. and reacted to the point where form:

ing due consideration to the test previously made in the case of the regulator we determine the condition of inactivation of the OH groups and condition .of resiniflcation by electrometric de- 5 terminations and thereby determine the resinification so far as coherer is concerned. The reaction is carried on after the formaldehyde is tied up with the condenser set at distillation, distilling at a vacuum of approximately 28% inches 10 v of mercury in order to eliminate further amounts of water so that the average composition of the resinous fluid will be within the limits called for.

While it is realized that additions of formaldehyde have previously been made in compositions by slowly adding formaldehyde to the phenol while reactlon'is proceeding, my reaction is carried out under such conditions that a por-" tion of the formaldehyde is added in quantity sufllcient to give a certain percentage of more so highly reacted products, in the form'of the regulator, and this reaction is carried out at relatively high temperatures, and then after determination of the exact degree of reactivity into more highly polymerized products the kettle g5 charge is cooled down to a temperature where the reaction will be moderated, it being found that at relatively high temperatures the tendency is to produce resinificationproducts of the highly reacted type and therefore I am by this means able :0

to. direct the reaction in such manner to insure the proper proportion of regulator and subsequently the proper proportion of coherer with definite tests without need for segregation which can be carried out through differential solubility if desired, and I am enabled to definitely check the average conditions prevailing for these four important components. Were average resinification definitelydetermined and if the percentage of incoherer (water) is excessive. the resin in o the still is cooled to a temperature approximately 120 F. and higher vacuum if necessary is maintained and the excess of water is eliminated by low temperature distillation.

A reaction carried out in this manner can be fop-for thicoherer and that called for for the C. P. sodium hydroxide dissolved in a as stated elsewhere, such preparation is not preeluded.

In my preferred material the water content including some other volatiles will represent about 35%, and the other evaluations will be carried out within as close limits as possible called for in ,my data specification under my choice material.

Example I I.An equivalent proportion of trioxymethylene may be substituted for the first increment of formaldehyde in Example I. I have found that trioxymethylene has a tendency to react rapidly and produce the more highly resinifled products which function as the regulator portion of my converting. fluid. Where a product having the lower proportions of. incoherer are desired, and where eillcient vacuum pumps arefi not available for removing water, the use of trioxymethylene for producing, the regulator component is advantageous.

Example IlI.' It follows /likewise, that should I sodesire I can modify the formula sofar as the proportion of' phenol and formaldehyde is concerned and add a previously reacted product of high viscosity or a substantially solid soluble and fusible resin to the phenol required to provide liquid, and not strictly as limiting factors, since it will be obvious to those skilled in the art that variations may be made in the resinous liquid if compensated for in the dry powdered resins mixed The viscosity given in the above table was determined 'on a Stormer viscosimeter at 25 C. Since the viscodty of the liquid component of my process plays an important part, the limits are rather-narrow. A product having a viscosity exceeding 3'15 centipoises is not suitable. The resinous liquid should also have a low surface tension and low internal coherence. readily wet and are easy to mix with abrasive grains and produce uniform coatings thereon.

Furthermore, such mixes when wet have but little tendency to become-sticky and tacky and to form agglomerates with the abrasive grains. Briefly, such mixes are relatively loose in character and present all surfaces of the wetted grains to the dry powdered resin.

The pH values are thevalues as determined on temperatures.

Such liquids 5 the coherer and some of the bridging and overtherewith. Generally stated, the pH value of lapping fringes between the coherer and the regu-' my preferred" material is so gauged that it is lator and then carry out the reaction at lower preferably somewhat below the point at which a temperatures to provide substantially a reaction marked buffering tendency is indicated. That is,

product which will produce these lower polyup to a pH of approximately only a small 10 merization products, and in this manner I will amount of base is needed to rapidly raise the pH provide a solution comprising the four comvalue and for the same reason when the dry pulponents in their average reactivity as called for 'verized resin is added the slight acidity of the in the tabulations. j resin rapidly lowers the pH value to a point where Example IV.--The entire fluid can be comthe resin separates from the aqueous solution and 5 pounded of previously produced ingredients by the water is probably external to the mix.

having previously provided materials as char- Water solubility ratio is determined by weighacterized for the coherer, that is low resiniflcaing out a definite amount of the converting liquid tion reaction products, together with a product and slowly adding water thereto until a permamore highly reacted, as'called for-under regunent turbidity appears. The ratio by volume of lator, and adding thereto the required amount of the water added to the amount of resinous liquid ineoherer and solubilizer and adjusting theforused for the test is the water solubility factor, mula as to inactivation of OH groups by the that is, when based on a phenol-aldehyde reacaddition of phenol or incipient reaction products tion product, and it is to be understood that apsuchasphe'nol alcohols and balancingthe formula parent turbidity due to added water insoluble within the limits prescribed for my choice resinreagents is to be disregarded as normal apparent ous liquid requirements. turbidity, such adulteration giving pseudo end The aqueous alkaline resinous liquid should be points. This is likewise true of the water tolercontrolled within close limits as otherwise optiance in methanol. mum working conditions may not be produced; The water tolerance in methanol is based on a 80 thepreferred physico-chemical limits of the phenol-formaldehyde resin which is unadulterliquid may be thus charted and explained: ated with very water insoluble substances for the Resinous liquid data mama limits Possible 11mm Testconstsnts Law 01101 mm Low High Viscosity, centipoises, 25 0 so 100 200 so :15

40 all V uei Bcchnanelectromen-ie. 9.0 9.3 0.8 7.3 14.0w over ates soubility ratio by weight. Alkaline resin solution given as 1 1:28 1:3. 1 1:3. 6 1:1 1:5 finfifitt's fit 'itfi tta 's presen T o Kh? u it 61% 0% Si $285 xl s fgf 0.10 am 0.: 0.05- 0.40

. pescen o a relati e... simulates..- a on groups 0.08 0.12 0.1.1 0.01 1.2 Af'stsgeresiniilcationhctor 10 14.1 v as s 45 Water content, percent 26 45 10 66 fitd out w m conditions" s00 12.00 iaoo aoo asoo so Vacuum, mflmhourl .00 auo 20.00 n00 Q00 1 hand twsn into the 1 ditwfistgfinohs(ofl)mumaiflmflymsnuedbythp :tha t mskingof 00;:

or. mu m. alkalinematerialsireetooombine with phenolic (on groups 55 Gr. moles phenolic (Olligroupsinthsresinsolution reasons given under the test for water solubility ratio. This test is conducted to determine the water tolerance of solutions of the resins in methanol at a fixed temperature and pH. This temperature is taken at close to ordinary room satisfactory. Through experimentation it was found that 100 ml. of methanol to the 10 gram sample of resin solution is quite satisfactory.

The pH of the solution should be adjusted by the addition of alkali or acid to say a pH of 9. To carry out the test 10 grams of resin are dissolved in 100 ml. of methanol (multiples of; this proportion may be used if desired). thenrun in from a graduated burette and before cloudiness sets in the pH shouldbe adjusted to 9 with the addition of normal aqueous alkali or acid. Additional distilled water is then run in and the, point at which a permanent anddis- A temperature of 25 C. is quite Water is is taken as the water tolerance in ml. It might be stated that phenol, cresol, xylenol, etc. show a water tolerance of infinity. This is likewise true of the phenol alcohols. It is likewise true of a solution of say 25 parts of hexamethylenetetramine in cresol or phenol, the solution being unreacted. As resiniflcation proceeds the water tolerance varies inversely therewith and becomes lower and lower; and where the test is carried out on a product of similar characteristics and evaluations utilizing these different initial re-' agents should be checked against results obtained where phenol and formaldehyde is used. This isnecessary because the limits set for my preferred material are narrow and best operating conditions require that the product be kept within these narrow limits. a

The terms gram moles phenolic (OH) groups originally present", "gram moles phenolic (OH) groups in activated per 100 grams of resin solution", 'phenolic (OH) groups inactivated, per cent of original OH groups in the resin solution", ratio of alkaline material free to combine with phenolic (OH) groups", and A stage resiniilcation factor" will be treated collectively. I-might state that the degrees of resiniflcation we are dealing with in this test are all within the range described by Baekeland as A" stage. The determination of degree of resiniflcation and the factors of assistance in evaluating a useful resinous liquid havebeen developed particularly for the purpose of this specification, and as there is no published information .on this subject a rather lengthy explanationwill need to be given.

Thedata given is for the purpose of definitely evaluating the degree -of reaction and, the appraisal of this reaction product through definite numerical values; likewise, to obtain data as to resin concentration and to classify this resinous liquid as composed of a suitable admixture of the four components functioning as coherer, incoherer, regulator and solubilizer.

when using a Beckman pH meter equipped with a glass electrode, the phenolic (OH) groups can be determined by direct titration with a standardized alkali solution which provides a convenient and accurate method for determining the phenolic (OH) groups based upon the above fact. It is found that the phenolic (OH) groups play an important part in the process and as an indication of the degree of reslniflcation.

The determination of phenolic (OH) groups; Phenols are practically neutral bodies, but in water and certain other mediums they behave as very weak acids. Thus phenol possesses a dissociation constant of 1.3x comparable to other very weak acids such as arsenious and hydrocyanic. The alkali salts of the phenols are quite water soluble and yield aqueous solutions that are very alkaline and highly buifered. For the titration of phenolic bodies with alkali it is desirable to have the phenolic body completely in solution. Inasmuch as higher monhydric phenols as well asmost liquid resins are rather insoluble in water it is necessary to add a coupling points. fthasbeenfoimdthatmethanolisthe most suitable alcohol for this purpose. The ratio of water to methanol has an important bearing on the results, particularly upon the sharpness of the end point. Preliminary tests have shown 5 that a ratio of seven parts of water to twentyfive parts of methanol by volume is quite satisfactory. It is preferable to first dissolve the phenol or resin in the methanol and to then add the water; and in any instances wherethe 1 water tolerance of the solution is insufllcient to stand such a water concentration. special precautions have to be followed. In any event the pH of the solution at the starting point from which the amount of alkali for the titration is measured is adjusted to be closed to (7) The exact temperature is not important so long as it lies between 15 centigrade and 40 centigrad Once set, the temperature compensator of the Beckman apparatus should be left alone even 90 though the temperature may change during the .cours'e of the titration. During the'titration the solution should be kept continuously agitated by means of a suitable stirring device.

The alkali solution for the titration consists of 2 a normal solution of NaOH made up in one liter of aqueous methanol of the above referred to composition (7 vol. of water to vol. methanol). The pH is most conveniently measured by means of a Beckman pH meter provided with a glass electrode. As alkali is run in the pH increases rapidly at first and then more slowly. and eventually the point is reached where the pH practically ceases to go up upon further addition (The pH mayvirtually be constant of NaOH. as more alkali is 'added.) The ml. NaOI-f required to reach this point starting from an original pH of seven (8.5-7.5) is recorded. Due to the fact that this end point is oftentimes not very sharply defined (as the changes in pH per 4 ml. NaOH near the end point are barely perceptible) great care must be exercised and it is suggested that as this end point is being approached the NaOH be let run in in two (2) or two and onehalf (2%) ml. portions and in this manner, with a little experience, the total ml. NaOH required can usually be established to within plus or minus nols, alpha and beta-naphthol, para-tertiaryamyl-phenol, para-tertiary-isobutyl-phenol, catechol, hydroquinone, resorcinol, etc., as well as liquid phenol aldehyde resins-when using such sized samples as to contain somewhere between 0.02 and 0.20 gr. mols. phenolic (OH) groups the.

following simple relationship exists: gr. mols. (OH) groups=0.'l83xgr. moi. NaOH used in the titration. 1

This electro-metric titration method thus permits of an accurate and relatively simple determination of phenolic (OH) groups.

Acids a dissociation constant near that of the phenols should be absent; fortunately in practice such acids are seldom encountered.

Phenols containing highly electro-negative substituted groups such m 01.81, N02. and etc. are too strongly acid in character to permit of their evaluation by the above formula.

The test is conveniently carried out as follows,

bearing in mind all the aforementioned charac- 7| terlstics: ten (10) grams of phenol or phenol- -aldehyde resin is dissolved in 250 ml. of methanol.

10 ml. of water are then added and the pH is then brought to between 7 and 7.5 by the addition of the above referred to NaOH solution or of concentrated C, P. hydrochloric acid (added drop by drop) depending upon whether the resin or phenol is acid or alkali. 60 more ml. of water are then added but if a precipitate starts forming before this full 60 ml. are added, it is best to first run in about half of the NaOI-I that will be required for the titration and to then add the remaining water. The alkali solution is then let run in until the above referred to end point has been reached. The total ml. NaOH run in from the time the solution had a pH of 7 to 7.5 is recorded and if this figure is multiplied by "1.82xl0- we have gr. mols. phenolic (OH) groups contained in 100 grams of the material being tested. (In case the gr. mols. phenolic (OH) groups is outside the range of 0.02 and 0.20 a larger or smaller sample should be taken).

Quantitatively the phenolic (OH) groups are calculated in terms of gr. mols per 100 grams .of material. The electro-metric titration method furnishes the necessary data for this computation which may be equated as follows: gr. mols. phenolic (OH) groups per 100 grams of material=ml. normal NaOH used in titrating 10 grams of sample multiplied by the constant 732x10 By the term original phenolic (OH) groups-- symbolized by (OH)...- is designated the gr. mols. of phenolic (OH) groups originally possessed by the phenols that enter into the making of 100 gramsof material tested.

Inactivated OH groups represent groups that were originally present, but after resinification no longer are detected by the electro-metric titration. l

' Gram moles of phenolic (OH) groups inactivated per 100 grams of resin solution is determined by determining the gram moles of phenolic '(OH) groups-in 100 grams of the material being tested, and subtracting this result from the gram moles of phenolic (OH) groups originally present. The difference is the inactivated" phenolic groups.

.Pheriolic (OH) groups inactivated per cent of the original phenolic groups in the resin solution is calculated from the gram mols. phenolic (OH) groups inactivated immediately preceding.

The ratio of alkaline material free to combine with phenolic (OH) groups is readily determined in the following manner: The resin as usual is dissolved in the methanol and the '70 ml. of water are added or as much of it as possible without forming a precipitate when the pH is reduced to 7. The pH of the solution before the addition of acid is recorded. The acid is then added drop by drop to bring the pH to 7, as is explained in the description of the electro-metric titration method and then there is recorded theml. noraction between a phenol and an aldehyde pro- 7 ceeds. The following tabulation gives in a broad way the per cent inactivated phenolic perature.

groups at various stages of reaction between the original mixture of phenol and aldehyde and the fully reacted C stage resin:

d "A" stage resins.

"0" stage:

The A" stage resiniflcation factor symbolized by F. is calculated from the formula V (OH)M I-F (OH or where (OH) in=inactivated phenolic (OH) groups (OH)or=gram moles of phenolic groups originally present (OI-Di- ='gram moles of phenolic groups found in resin The formula is, of course, useful only when less than half of the phenolic (OH) groups have been inactivated, i. e. up to and including "A" stage resins. v

It has been found that in a solution of phenol and aqueous formaldehyde catalyzed by a strong alkali as NaOH even at room temperatures but more rapidly at higher temperatures a reaction takes place which results in the gradual disappearance of free formaldehyde-probably due to the formation of phenol alcohols and analogous compounds. During this time the viscosity will be found to have gone up somewhat and the (0H)in will have taken on a definite value, but even after all the formaldehyde has practically disappeared as such the (0H)in will continue to go up at a rate and to a final value depending upon the original concentrations and the tem- On the other hand, one can take an already prepared liquid resin and add formaldehyde to it and obtain an (010m that may be equal to the (OHM of the above virtually formaldehyde free solution. In short, we can prepare numerous aqueous alkaline phenol-formaldehyde solutions possessed of one and the same (OHM, (0K).- and (OI-1):, yet these solutions are chemically and physically not identical. This shows quite plainly that the (OH) group data taken alone does not necessarily differentiate liquid resins from one another This does not mean, however, that blends satisfactory for my purpose cannot be made and therefore such blends are notprecluded if such blends provide the wet-dry product of my invention. Further on in the specification further data is given which will assist in the evaluation and the production of blends of this type and will indicate the limits within which results most favorable for this work are attainable;

When resins made by reacting phenol, aqueous formaldehyde'and NaOH are compared with mixtures of formaldehyde, phenol, water, NaOH and completed and/or partially completed A stage resins in such proportions that the (OI-Du, (OH) or, Fm and viscosity is substantially the same for the mixture as for the said reaction product,

it has been found that there are some diner-- ences. Some of these admixtures may even produce sticky mixes which remain wet while others may act satisfactorily. These differences are particularly apparent where the difference lies in a therefore be definitely determined by evaluating an average value and is not to be interpreted as v the material on the basis oi all of the units 01' characterization given by me.

It is worth bearing in mind that l ke represents meaning that the whole oi the resinous constituents. of the resin are w of one and the same degree of reslniilcation. Liquid resins depending upon the precise original composition and procedure i'ollowe'd in the making of the resin,

may in general terms be described as consisting of mixtures of phenol-alcohols and phenol-aldehyde resins in various stages of res'iniilcation, possessing Fm factors that may range all the way from zero to that of a completed A stage resin.

Water content, per cent, is calculated on the total weight of the coating liquid. ."Ihe term water. is used in its ordinary sense and as to whether the water is present as an addition product or results from some chemical reaction or represents an aqueous alkaline solution, is immaterial so far as my definition and limits are concerned.' It may represent the liquid product of a non-resinous and liquid nature which remains with the resin after the reaction oi a phenol-formaldehyde material has been completed, or it may represent water plus some other suitable ingredient such as trlethanolamine or other alkali such as sodium hydroxide, or a solution suitable to provide a wet-mix which is seliconverting at ordinary room temperatures to a dry mix comprising substantially individual grains.

Rate of evaporation, per cent loss, is deter mined by spreading a sample oi the material I under test weighing approximately 0.2 gram as a thin layer on a 50 mm. diameter watch glass, and allowing it to stand for a given length of time in the open air. The figures given for the preferred limits were obtained by carrying out the test at an average room temperature of 78 1". and an average relatively humidity of Weighings were madeat the end of 80 minutes and the loss in weight taken as the amount evaporated, from which the percent loss was calculated. "The rate of evaporation, per cent loss vacuum was obtained in a similar manner, except that the watch glass containing the specimen under test was placed in a vacuum desiccator over calcium chloride, and a vacuum of approximately 29% inches. of mercury was maintained during'the test. The temperatures during the tests was approximately 75 F.

In the making of the preferred solution I flnd that it'is most satisfactory to introduce the al-- medium. .Whlie Imay start witha solid resin or liquid resin and cut this with an alkali, under these conditions it is preferable that the solution be allowed to stand for a number of hours prior to use or else that the product beheated somewhat to provide an alkaline solution which will quickly convert itself to the dry mix upon use.

I claim:

l. The method of making a resinous liquid ior admixture with flllers-anddry pulverized synthetic resins to produce a wet mixture which is self-convertible to a dry mix capable oi. being cold molded, which comprises mixing from 10% to 40% of a phenol-aldehyde reaction product wherein from 30% to 50% of the phenolic (OH) groups are inactivated, with from 20% to 70% of a phenol-aldehyde reaction product wherein only from 5% to 20% of thephenolic (on) groups are inactivated, and adding alkali and water thereto to produce a homogenous liquid having a viscosity below 375v centipoises.

2. An alkaline liquid phenol-aldehyde resin 01 low viscosity for admixture with tillers and dry pulverized synthetic resins to produce a wet mixture which is self-convertible to a dry mix capable 3. An alkaline liquid phenol-aldehyde resin for admixture with fillers and dry pulverized synthetic resins to'produce a wet mixture which is self-convertible to a dry'mix capable of being coldmolded, said liquid resin having a viscosity lower than 20 0 centipoises at 25 C., originally tween 0.25 and 0.80 gram mol. of phenolic (OH) groups per grams of the said liquid resin and resinified to a point where between 18 and 27 per cent of said phenolic (OH) groups are-inactivated, said liquid resin containing water of from 25 to 45 per cent.

4. An alkaline liquid phenol-aldehyde resin for admixture with fillers and dry pulverized synthetic resins to produce a wet mixture which is self-convertible to a dry mix capable of being cold molded, said liquid resin having a viscosity in centipoises at 25 C. within the range of 100, originally having phenols in such quantity as to contain between 0.25 and 0.80 grammol of phenolic (OH) .groups per 100 grams of the said liquid resin and resinified to a point where within the range or 22 per cent oi said P o (OH) groups are inactivated, said liquid resin contain- 7 ing water within the range of 35 per cent. 5. An alkaline liquid phenol-aldehyde resin for admixture with fillers and dry pulverized synthetic resins to produce a wet mixture which is self-convertible to a dry mix capable of being cold molded, said liquid resin having a viscosity lower than 200 centi ises at 25 C., originally having phenols in such quantity as to contain between 0.25 and 0.80 gram mol of phenolic (OH) groups per 100 grams 0! the said liquid resin and resinifled to a point where between 18 and 2'7 per. cent of the phenolic (OH) groups are inactivated, said liquid resin having a water content of from 25 to 45 per cent and a pH value 01' from 9.0 to 9.8.

- 6. An alkaline liquid phenol-aldehyde resin for admixture with fillers and dry pulverizedisynq thetic resins to produce a wet mixture which is sell-convertible to a dry mix capable oL-being cold molded, said liquid resin having 'a'viscoslty 0.25 and. 0.80 gram mol of phenolic (QH) resin and lower than 200 centipoises at 25 C., originally i having phenols in such quantity as to contain beresinified to a point where between 18 and 7 per cent of said phenolic (OH). groups are inactivated,- said liquid resin containing water 01 from 25 to 45 per cent and having a ratio of alkaline material tree to combine with phenolic (OH) groups of from 0.08 to 0.15.

'7. An alkaline liquid phenol-aldehyde resin for admixture with fillers and dry pulverized synthetic resins to produce a wet mixture which is self-convertible to a dry mix capable of being cold molded, said liquid resin having a viscosity lower than 200 centipoises at 25 0., originally having phenols in such quantity as to contain between 0.25 and 0.80 gram moi oi. phenolic (OH) groups per 100 grams or the said liquid resin and resinified to a point where between 10 and 40 per cent of the phenolic (OH) groups are inactivated, said liquid resin having a ratio or alkaline material free to combine with phenolic (OH) groups of from 0.01 to 1.2, having also a water content of from 25 per cent to 45 per cent, having also a pH value above 7 and having an A" stage resinification factor of from 10 to 25.

8. An alkaline liquid phenol-aldehyde resin for admixture with fillers and dry pulverized synthetic resins to produce a wet mixture which is self-convertible to a dry mix capable of being cold molded, said liquid resin having a viscosity lower than 200 centipoises at C., originally having phenols in such quantity as to contain between 0.25 and 0.80 gram mol. of phenolic (OH) groups per 100 grams of the said liquid resin and resinified to a point where between 18 and 7 per cent of the phenolic (OH groups are inactivated, having a ratio of alkaline material tree to combine with phenolic (OH groups of from 0.08

to 0.15, having also a water content oi from 25 per cent to 45 per cent, having also a pH value between 9.0 and 9.8, and having an A stage resinification factor 01 from 0 to 25.

. 9. An alkaline liquid phenol-aldehyde resin for admixture with fillers and dry pulverized synthetic resins to produce a wet mixture which is self-convertible to a dry mix capable of being cold molded, said liquid resin comprising between 20 and '70 per cent of low reaction resinous products and between 40 and 10 per cent of high reaction resinous products, the said liquid resin originally having phenols in such quantity as to contain between'025 and 0.80 gram mol. of phenolic (OH) groups for 100 grams of the said liquid admixture with. pliers and dry pulverized synthetic resins to produce a wet mixture which is self-convertible to a dry mix'capable of being cold molded, said liquid resin comprising between 20 and '10 per cent with an optimum of about 40 per cent or low reaction resinous products and between 40 and 10 per cent with an optimum of approximately 30 per cent or high reaction resinous products, the said liquid resin originally having phenols in such quantity as to contain between 0.25 and 0.80 gram mol of phenolic (OH) groups per 100 grams of the said liquid resin and resinifled to a point where the per cent of phenolic (OH) groups inactivated averages between 10-and 40 per cent, with an optimum of between 18 and 27 per cent, the per cent phenolic (OH) groups inactivated in'the aforesaid low reaction products being between 5 and per cent and that of the high reaction products. being between and 50 per cent.

11. The method or making a liquid phenolaldehyde resin for admixture with fillers and dry pulverized synthetic resins to produce a wet mixture which is self-convertible to a dry mix capable of being cold molded, which consists in reacting the phenol at high reaction velocity with only a portion of the aldehyde present to produce between 10.- and 40 per cent of high reaction products of resiniflcation, wherein between 30 and per cent oi the phenolic (OH) groups are inactivated, and then completingthe reaction by adding additional increments of the aldehyde to 

